modular chassis - Computer Definition

A hardware device that is designed for expansion and accepts a variety of plug-in modules of different types. High-end network switches and routers are often built with a modular chassis. See line card.

A Modular Chassis

Cabletron's earlier MMAC PLUS was a network hub that supported Ethernet, Token Ring, FDDI and ATM networks. The boards plugged into the backplane, which was a bridge between the various topologies. (Image courtesy of Cabletron Systems.)